Flight Experience Sydney - What a beauty! This is a 1973 Learjet 25B, with the mandated hush kit for stage 3 noise compliance. Airplanes like this, with turbojet engines, are very loud.
Decaff's Requested Tutorials - Hush Kit - YouTube
Hush-Kit Book of Warplanes Review - by Hush Kit
The Hush-Kit Book of Warplanes Typhoon " Essential T-Shirt for Sale by HushKit | Redbubble